School Foucault pendulum

A Foucault pendulum was assembled for a university/high-school physics course. The pendulum is 2.85 m long and the mass of the bob is 4.70 kg. A new technique based on the spark burned points on a sheet of paper was used to register the pendulum's motion. A Ruhmkorff induction coil was used as a high-voltage source. Plots of the elliptical trajectories (except the first trajectory, which is a straight line) can be created and the angles between the major axes of the ellipses can be determined after assigning the coordinates to the burned points. (paper)